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J. B. N. FOURNIER vAND C. A. LEMAIRE, OIF PARIS, FRANCE. Letters .Patent No. 89,757, dated May 4, 1869.

BERCY-MNT I N ELECTRO-MAGNETIC TELCPERA'I'URE ALARMS,

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To all whom it 'nur/y concern Be it known that we, J. B. N. FOURNIER and C. A. LEMAIRE, of Paris, Rance, have invented an Iniprovenient in Thermometers; and we do hereby leclare the following to a full, clear, and exact descn'ption ofthe. same.

'Our invention consists of the combination with u thermometer of certainplates, or ribs adjustable on the scale of the thermometer, and connected to a wire leading to one pole of a galvanic battery, and certainy alarm-mechanism arranged between the battery and the pointer ofthe tbemiometer, which pointer is con nected to the opposite pole of said battery, all as fully described hereafter, so that a galvanic circuit is es'- tablisbed, and an ala-rm given whenever a variation of temperature occurs beyond a limit previously determined upon.- In order to enable others skilled in the art to make and use our invention, we will now proceed to describe its construction and operation, reference being had to the accompanying drawing, which forms n. part of this speciication, and in which- Figure 1 is aface view of our improved thermometer;

and

Figure 3, a rear view, the back of the case being removed.

The case of the instrument, in the present instance,

consists of a cylindrical portion, A, and an elongated` portion, B, an ordinary spirit, or mercury-thermome ter being secured to the outside of the latter.

Within the case is a compound metallic bar, b, such as is employed in metallic thermometers, and to the 'lower end of this bar is secured a curved ratchet, '1), the teeth of which are adapted to those of a pinion on a shalt, a, extending throughan openingrin the centre of a circular plate, E, of slate or other non-conductor of electricity. A

In the face of the circular portion A of the instrument is a curved opening, through which may be seen a curved graduated plate, O, and over the latter moves a pointer, X, secured to the shaft a. A

' To a sleeve surrounding, but insulated from the shaft a, are hung two adjustable arms, L L', whiclrextendV beneath, and are bent down over the face ofthe plate C, the ends of the arms being formed into fingers t t', and on each arm, beneath the plate O, is a curved n'b, or projection z, or af, for a purpose described hereafter.

- j On one of -the arms, L L', is a stud, G, to which is connected a wire` leading to a pole of a galvanic battery, and to an arm, P, in which turns the inner end of the 'spindle a, is connected a wire, leading to the Figure 2, a vertical section on the line 1'- 2,ig. 1,

other pole of the battery, suitable alarm-mechanism being placed in connection with one ofthe wires, so as to he operated when a galvanic circuit is established.

The aims L L' may be adj usted soas to occupy any desired position on the plate c, and the pointerx, so long as its vibration 1s limited to the space between thesetwo arms, operates in the ordinary manner. If, however, on an unusual increase or diminution of tempeinture, the pointer should be brought into contact with one or the ribs or projections a: a', a continuous metallic connection 'will be established between the two wires, through the medium of the sha a, pointer x, arm L or L', and its rib, the electric circuit bein thus completed, so as to set in operation the alarm mechanism before alluded to. l

By adiusting thel arms L L' in close proximity, an alarm will be sounded in case of but a slight variation of temperature, while, as the' distance between the' arms isincieased, the extent to which the pointercan move without sounding an alarm is enlarged. j. The instrument may be employed for various purposes, as for indicating any variation from the proper temperature in hothouses, hospitals, public halls, stcrerooms, &c., 'or in coal magazines, .or .hay-ricks, to indicate danger of irefrom a sudden or too great increase oftemperature. l Y

It will be seen that the-ribs or projections a: z', although so placedA that the pointer may come in contact with them, do notfinterfere with' the free movement of the pointer beyond the points where the alarm must be given, the straining or breaking of the mechanism being thus prevented. f'

Withoutclaiming broadly thel combination cfa-battery and alarm, with a pointer connected to the battery, and moving over a graduated arc, provided with projections also connected to the battery,

We claim as our inv ntion, and desire to secure by Letters Patent'- The within-described'mbinanon ofthe compound metallic har b, a-pointer, x, l'operated by the bar, a graduated arc, c, and adjustable ribs, or blocks z'a,

so constructed as to permitthe' pointer to pass over,

but iucontact with the same, when the 'said pointer and blocks are connected to the wires of a batry, as se: faith..

In testimony whereof, we have signed our names to this specication, in the'presence of two subribing witnesses. -v

' FOURNIER.

LEMAIRE. Witnesses:

F, Onco'n, G. Brumm). 

